Concrete mat



W. R. PIERSON CONGRETEQMAT Filed Sept. 2, 1952 3 Sheets-Sheet l gwuc/wbot/ "R. Pierson CONCRETE MAT Filed Sept. 2, 1932 3 Sheets-Sheet '2 2o 7 Q0 [3 31:' 5 7 24 24 I '24 Dec. 11, 1934. w. R. PIERSON CONCRETE MAT Filed Sepf. 2, 1932 5 Sheets-Sheet 5 \Vesley Pierson Patented Dec. 11, 1934 UNITED STATES PATENT OFFICE 9 Claims.

My invention relates to mats for use on river banks and similar surfaces subject to the action of water, and has for its object to provide a flexible concrete mat which may be used to prevent 5 erosion and to resist the scouring action of water and which may be readily applied to irregular surfaces.

An object of the invention resides in constructing the mat with a number of slabs and in providing tie members for connecting the slabs together.

Another object of the invention resides in spacing the slabs and in employing a flexible tie member extending between the slabs capable of bending at such localities by means of which the slabs may have relative movement to cause the same to conform to the contour of the surface on which the mat is to be used.

A still further object of the invention resides in constructing the slabs upon the under surfaces thereof with ribs projecting outwardly therefrom and adapted to become imbedded in the earth on which the mat rests to prevent lateral movement of the mat with respect thereto.

A feature of the invention resides in constructing the slabs elongated and in arranging the ribs in longitudinal relation with respect thereto.

An object of the invention resides in providing a transverse rib on each of the slabs intersecting the longitudinal rib for supporting the slabs in upright position during the building of the mat.

A still further object of the invention resides in arranging the slabs in rows and in staggered relation with respect to one another.

Another object of the inventionresides in arranging the ties so that the end ties of the ad-- joining slabs in one row pass through a single slab in an adjacent row.

A feature of the invention resides in construct- 40 ing the slabs substantially triangular in cross section with the bases uppermost, and in applying the tie members to the slabs near the bases thereof.

An object of the invention resides in connecting a number of slabs together to form a mat section and in providing means for connecting the sections together to form a composite mat of any desired extended area.

A still further object of the invention resides 50 in constructing the slabs with holes therethrough and in threading the slabs in alternate relation upon a number of ties whereby the slabs may be erected upon the site.

Other objects of the invention reside in the novel combination and arrangement of parts and in the details of construction hereinafter illustrated and/or described.

In the drawings,

Fig. 1 is a plan view of a mat illustrating an embodiment of my invention.

Fig. 2 is a cross sectional view taken substantially on line 22 of Fig. 1.

Fig. 3 is a plan View of one of the mat sections shown in Fig. 1 and drawn to a somewhat larger scale.

Fig. 4 is a fragmentary plan view of a portion of the structure shown in Fig. 3 and drawn to a still larger scale.

Fig. 5 is a fragmentary sectional View taken on line 55 of Fig. 4 and drawn to a larger scale.

Fig. 6 is a fragmentary plan view similar to Fig. 1 of a modification of the invention.

Fig. '7 is a fragmentary plan view similar to Fig. 4 of the form of the invention shown in Fig. 6. 2

Fig. 8 is a perspective view of one of the slabs used with the form of the invention shown in Fi 7.

Fig. 9 is a perspective view of still another form of slab capable of use with my invention.

In flooded areas considerable difiiculty has heretofore been encountered due to scouring and erosion of the soil and particularly on river banks. Heretofore it has been customary to place rip rap or willow matting on such surfaces for the purpose of retaining the surface in its normal condition. Such construction is extremely expensive and requires considerable time and mate rials in addition to not being permanent. The present invention provides a flexible concrete mat which may be applied tosuch surfaces and which may be quickly and readily installed and when once installed will conform to and retain the contour of the ground as desired.

My invention as best shown in Fig. 1, comprises a mat which is indicated in it's entirety by the ref erence character A. In the form of the invention shown in this figure the mat is illustrated as being constructed of a number of mat sections 10, 11, 12, 13, 14, 15, 16 and 17 which are arranged adjacent one another and connected together in any suitable manner. Each of these sections being identical in construction, only the section will be fully described which is shown in detail in Figs. 13 to 5 inclusive. The mat section 10 consists of a number of concrete slabs 18 identical in construction which are connected together through flexible metal ties 19 whereby the mat may be bent so as to conform to the surface on which the .mat is to be placed.

Each of the slabs 18 is constructed elongated in form and is substantially triangular in cross section as shown in Fig. 5. The slabs 18 are ar ranged with the bases 20 thereof uppermost and with the vertexes of the triangle extending downwardly as indicated at 21 to form elongated ribs "which extend longitudinally of the slabs and which serve as keys for engagement with the ground to prevent movement of the mat. The tie members 19 consist of flexible bands, wire or rods of suitable material which are imbedded in 'the concrete near the bases 20 thereof; As will be noted in Fig. 5 the various slabs 18 are spaced from one another, leaving portions 22 of the ties l9 exposed between adjacent slabs. This permits of bending of said ties between the slabs whereby the slabs may be caused to rest upon the ground and to conform to the contour thereof. Each of the slabs 18 is provided with one or more longitudinally extending reinforcing rods 23, 24 and 25 for stiffening andreinforcing the same. b

At certain of the slabs 18 which I have indicated at 26, loops 2? are employed which extend outwardly from the ends of these slabs. These loops have the ends 28 thereof hooked and imbedded in the concrete and serve to anchor the mat and to provide means whereby adjacent mat sections may be connected together. Similarly in the end slabs 29 are formed loops 30 which are identical with the loops 2'? and which project outwardly from the lateral edges of the slabs. Any number of ties 19 may be employed for connecting the slabs together, at least two being required for each mat section.

In the construction of the mat sections the ties 19 are laid in the mould and the concrete poured about the same to cause said ties to become permanently imbedded in the slabs. The various sections so constructed form individual mat sections or units which may be transported and laid as a unit in the building of the mat.

In construction, the mat sections are arranged none at a'time upon the surface to be covered and *disposed in juxtaposed position as illustrated in Fig. 1 These mats are preferably arranged so that the slabs extendin a direction at right angles to the direction in which the mat would be most likely to move through the action of the water to whiohthe mat is to be subjected. Also the sections may be arranged in staggered relation with respect to one another to strengthen the structure and prevent erosion of the earth along lines defined by the joints between sections. The sections are tied together by wire which is inserted through the various adjoining loops 30 and 27 and twisted together so that a rigid unitary structure is formed.

Where it becomes necessary to anchor the mat the same is accomplished in the usual manner. In Figs. 1 and 2 I have shown a number of dead men 32 which are arranged about the mat and buried in the ground in the usual manner. These dead men have cables 33 attached to them which are secured to certain of the loops 2'7 and 30 of the various mat sections. By means of this construction the mat may be anchored soas to assist in preventing shifting of the same upon the surface on which it is erected and to prevent the mat being washed away in the event of heavy floods or violent water action.

If desired, the slabs may be erected one at a time and connected to one another to form a composite mat without the use of the precast mat sections as shown in Fig. 1. A mat capable of such use has been illustrated in Figs. 6 to 8 inclusive. The slabs used in this construction are shown in detail in Fig. 8 and are designated by the reference character 35. These slabs are similarly constructed to the slabs 18, being substantially triangular in cross section, and are each formed with a base portion 36 and a vertex portion 3'7 constituting a rib or key adapted to extend into the earth on which the mat is to be laid. The slabs instead of having ties imbedded therein are constructed with holes 38 and 39 which are situated at the outer quarter points of the slab. In other words, the hole 39 is one quarter the length of the slab from the corresponding end thereof and the hole 38 is similarly situated from the opposite end.

In the erection of the mat shown in Fig. 6 a number of ties 40 are employed which may be constructed of wire or any other suitable material. Two of the slabs are first arranged end to end and a tie looped through the holes in the adjoining ends thereof. A third slab is then arranged endwise with respect to the first two and a second tie looped through the two end holes in these slabs. This procedure is continued until ties extend through all of the holes of the slabs. The second row of slabs is then threaded upon the ties secured to the first row of slabs and so arranged that the slabs become staggered in adjacent rows as clearly. shown in Fig. 6. The holes in the slabs are large enough so that two or more wires may be inserted through the same. This permits of splicing the ties and of attaching the ties in the end slabs to the slabs in an effective manner. This procedure is continued until a mat of the proper size has been obtained. Thereafter the ends of the ties may be twisted together to complete the structure.

At the ends of the mat alternate spaces will be formed between the end slabs which are equal to half the length of the slabs." If desired, half length slabs, such as indicated at 41 may be employed which are inserted in between the full length slabs and which cause the slabs to project evenly at the ends of the mat.

It will readily be comprehended that the mat disclosed in Fig. 6 may be caused to accurately conform to the contour of the ground upon which the mat is to be built. Due to the fact that the ties are near the upper surfaces of the slabs the mat readily conforms to concave formations of the ground. Due to the fact that the extended portions of the slab on the under surface thereof are triangular in shape the said portions also permit. the mat to follow concave surfaces extending laterally of the slabs. To permit of the mat, to follow concave surfaces in the direction of the length of the slabs, said slabs are also beveled inwardly at the ends as indicated at 42 in Fig. 8.

In the handling of the slabs where the same are individually threaded upon the ties some difficulty may arise in causing the slabs to maintain an erect position when set upon the ground. To overcome this difficulty each of the slabs 35 is constructed with a cross rib 44 which intersects the rib 3'7 and isdisposed near the center thereof. These ribs are preferably offset so that the same clear one another when the slabs are arranged in adjacent position. When, however, th slabs are arranged as shown in Fig. 6, the ribs 44 are likewise offset from the corresponding ribs on adjacent slabs and no interference results so that the said slabs may readily follow convex formation of the ground. The mat shown in Fig. 6 may be anchored to dead men 45 and 46 through cables 47 and 48 as previously described, said cables being attached to loops or eyes 49 and 50 secured to certain of the slabs 35 constructed for this purpose.

My improved slab may also be constructed in a substantially square form as shown in Fig. 9. In such case an inverted pyramidal projection 51 is employed which restrains this slab from lateral movement in any direction. The slab 52 may be constructed with holes 53 and 54 so that the slab may be threaded upon ties extending in two directions at right angles to one another. Due to the fact that the slab shown in Fig. 9 leaves spaces between all adjoining slabs in which the earth may extend, a mat constructed of such slabs resists movement in all directions. No care need hence be exercised in the selection of the direction in which such slabs are arranged.

My invention may be used for various purposes and particularly for the purpose of stopping erosion and scouring of the soil due to the action of water on the same. My invention can be used to take the place of rip rap or willow matting and may be applied to river banks, lake bottoms, etc. and can be used on dams, road banks or spillways. My invention may also be used to form an open drain or conduit for the conveying of water from one locality to another.

My invention is particularly advantageous in that the cost per square yard covered can be materially reduced over and above the cost of rip rap or willow matting having the same resistance to scouring or erosion. The mat can be constructed quickly and economically and when once installed will be permanent. Where the mat is constructed in sections the sections can be quickly placed by suitable machinery and the mat erected in an extremely short period of time.

Changes in the specific form of my invention, as herein disclosed, may be made within the scope of what is claimed without departing from the spirit of my invention.

Having described my invention, what I claim as new and desire to protect by Letters Patent is:

1. A mat comprising a plurality of slabs arranged in juxtaposition, said slabs being substantially triangular in cross section and being arranged in inverted relation with their bases uppermost and the vertexes extending downwardly therefrom and engaging the ground and means for connecting said slabs together at their bases.

2. A slab for concrete mats comprising an elongated body portion, a longitudinally extending rib projecting from the underside thereof and disposed medially of the longitudinal edges of the slab, a transversely extending rib intersecting the longitudinally extending rib and disposed intermediate the ends of the body portion, said transversely extending rib projecting from the underside of the body portion the same distance as said longitudinally extending rib and means issuing from the elongated body portions and above said ribs for flexibly connecting the slabs together.

3. A slab for concrete mats comprising an elongated body portion, a longitudinally extending rib of V-shaped cross section projecting from the underside thereof and disposed medially of the longitudinal edges of the slab, a transversely extending rib of V-shaped cross section intersecting the longitudinally extending rib and disposed intermediate the ends of the body portion, said transversely extending rib projecting from the underside of the body portion the same distance as said longitudinally extending rib and means issuing from the elongated body portions and above said ribs for flexibly connecting the slabs together.

4. A mat comprising a plurality of slabs arranged in juxtaposition, each of said slabs being constructed with a body portion having substantially parallel sides and with a rib depending from the body portion, said ribs having beveled sides extending upwardly toward the body portion, and means issuing from the parallel sides of the body portions of said slabs and above said ribs for flexibly connecting the slabs together.

5. A slab for concrete mats comprising an elongated body portion, a longitudinally extending rib projecting from the underside of the body portion and disposed medially of the longitudinal edges of the slab, means projecting from the underside of the body portion and disposed on either side of said rib, said means terminating substantially in a plane containing the lowermost edge of said rib and means issuing from the elongated body portions and above said ribs for flexibly connecting the slabs together.

6. A mat comprising a plurality of slabs arranged in juxtaposition each of said slabs being constructed with a body portion and with a medial rib projecting downwardly from the underside of the body portion and adapted to enter the earth on which the mat rests to form earth keys therebetween for restraining the mat from sliding, said body portions at the upper surfaces thereof being closely positioned with respect to each other to reduce the effect of erosion and to preserve the earth keys, means for flexibly connecting the slabs together at the upper surfaces thereof to give flexibility to the slab without substantially increasing the spacing of the body portions of the slabs at the upper surfaces thereof said ribs being relatively narrow at their lowermost portions to give substantial widthto the keys at their bases.

'7. A mat comprising a plurality of slabs arranged in juxtaposition, each of said slabs being constructed with a body portion and with a rib depending from the body portion, and means issuing from the body portions and above said ribs for flexibly connecting the slabs together.

8. In combination with an earth foundation, a mat comprising a plurality of slabs arranged in juxtaposition, each of said slabs being constructed with a body portion and with a medial rib projecting downwardly from the body portion into the earth foimdation, and earth keys between said slabs for restraining the mat from sliding, said keys being of a width at their bases substantially equal to the width of the slabs.

9. In combination with an earth foundation, a mat comprising a plurality of slabs arranged in juxtaposition, each of said slabs being constructed with a body portion and with a medial rib projecting downwardly from the body portion into the earth foundation, and earth keys between said slabs, said keys being of a width at their bases substantially equal to the width of the slabs and of a height substantially equal to the height of the slabs.

WESLEY R. PIERSON. 

